Underreamer.



P. H. MACK.

. UNDBRREAMBR.

APPLICATION FILED DEO.11 1909. 982,5 1 4.

Patented Jan. 24, 1911.

2 SHEETS-SHEET 2.

l fri-5 UNITED STATES OFFICE. f

PATRICKVH. MACK, OF BRADFORD, PENNSYLVANIA, ASSIGNOR T0 OIL WELL SUPPLYCOMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA.

UNDERREAMER.

Specification of Letters Patent.

Patentedl Jan. 24, 1911.

Application led December 11, 1909. Serial No, 552,621.

Toall whom it may concern:

reamers; and I do hereby declare the following to be a full, clear, andexact description of the invent-ion, such as will enable others skilledin the art to which it appertains to make vand use the same.

This invention relates to the construction of that class of devicescommonly termed underreamers, employed for enlarging the borers of oilor Artesian wells ,where casing is inserted.' In drilling with thisclass of tools the tool is inserted and withdrawn through the casing,and therefore the underreamer must be collapsible so that the extremediameter of the cutting portion of the tool may be reduced at the timethe tool is passed throu h thelcasing.

The prevai ing types of underreamers are those wherein a slidingconnection between the stock and bits is effected either by means ofdovetailed ways or re uivalent interlocking parts, or by means o anaxial socket in theV stock for .the reception of the tangs of the bits,and in both of said types an interv posed spring or equivalent resilientmeans 1s employed for maintaining the bits in a normally expanded oroperative position.

My presen? invention relates more especially to thatltype ofunderreamcrs wherein the stock and'bits are slidingly connected by meansof interlocking parts, and has for its object such a formation andcombination of the coacting parts as'shall provide for the reducibilityof the diameter of the underreamer at its cutting portion, withoutcomplicating gr weakening the structure, and which will also provide fortaking up any lost motion which may arise from the wear or upsetting ofthe coacting arts.

To this end', in that class o underreamers wherein are combined abit-stock having av distance block for supporting the bits in theirprojected or operative position, and bits longitudinally movable on thestock, I form the recesses in the stock for the reception of thebit-'tangs with laterahwalls inclined to each other both outwardly andupwardly, and the bit tangs I form with lateral wallswhiclrcorrespondingly converge both outwardly and upwardly, whereby theinitial downward movement of the bits results in such clearance betweenthe stock and y bits as will not only permit the tool to free itself ofany accumulated fine sand or silt, but which will also permit of atilting movement of the bit, while the wedging of they tang when thetool is being operated takes up any lost motion and obviates anytendency ofthe bit to tilt, and such'a construction embodies the mainfeature of my invention.

There are other, minor, features of invention embracing particularcombinations and features of elemental construction, all as willhereinafter more fully appear..

In the drawings chosen for the purpose of illustrating my invention, thescope whereof is pointed out in the claims, Figure 1 is a'view inelevation of an underreamer embodying my invention. Fig. 2 is a similarView taken at right angles to Fig. 1. Fig. 3 is a longitudinal centralsection-taken 1n the plane of the line 3-3, Fig. 2, the bits being inthe expanded or operative position. Fig. 4 is a longitudinal centralsection similar to Fig. 3, the bits being inthe collapsed osition. Fig.5 is a transverse section taken 1n the plane of the line 55, Fig. 3.Fig. 6 is a transverse section taken in the plane of the line 6--6, Fig.`4. Fig. 7 is a detailed view in elevation of the lower'end of thestock, showing the tang recess of the stock adjacent to the ydistanceblock and abutments of the stock. Fig. 8 is a transverse -section of theunderreamer taken in the plane of the line 8--8, Fig. 4, showing, asapplied thereto, a clamp device for confining the collapsed bits whenintroducing the underreamer into the casing. Fig. 9 is a lonjgitudinalsection of the lower end of the stock and bits taken in the plane of theline 9 9, Fig. 8, and Fig. 10 is a view in elevation of the underreamershowing the application thereto of a tool for collapsing the underreamerfor introducing it into the casing.

Like symbols refer toilike parts whereverthe underreamer and B, B thebitsor cutters thereof. The stock A is provided at its upper end withtheusual pin p for attachment to the sub ordinarily interposed between theunderreamer and the drill rod and with the wrench seat 'w for thereception of the wrench used in attaching and detaching the -underreamerfrom the sub and drill rod.

At its lower end, and on opposite sides of 4the intermediate portion ofthe stock, are

upwardly and inwardly inclined abutments a for engaging the shoulders onthe bits B, B. Between the abutments a a atthe lower end of the stock,and integral therevthe reception of the spring which actuates the bitsB, B. The spring chamber a? is threaded at itsl lower end, in thedistanceblock, and is closed by a screw-plug ,P to retain the -actuatingspring in position in the axial spring chamberv a2.

The stock A, on diametrically opposite sides of the spring chamber a2,is provided with bit recesses a3, or recesses for the reception of thetangs b' ofthe bits B. They lateral walls of the recesses a3 of thebitstock converge, or are inclined, to each other both outwardly andupwardly, or in otherv Words, therecesses are dovetailed` in cross.

section, taper longitudinally of the stock for a distance correspondingto the length of the bit tangs, and are of uniform depth throughouttheir length. Said bit recesses a3 communicate at their upper ends, orare connected -by a transverse slot through which passes the ke C whichsupports the two Y bits B, B, an causes them to move in unison under theinfluence of the spring D.. The clearance between. the stock and bitswhich permits the escape of fine sand and silt, as well as permits ofthe tilting of the bits when collapsed, is effected by the downwardmovement of the. bits. At the lower end of the bit recesses a3 there isa slight increase in the width of the distance block as at a4 (see Figs.7 and 8) to accommodate the screw plug closure P of the borepor axialspring chamber a2, and on either side of said portion of thedistance-block the clearance between the bits and the stock may beincreased by slightly tapering the distanceblock asv at a. y f

B, B indicate the cutters or bits which are formed with tangs b, andwith upwardly and inwardly inclined shoulders b that engage theabutments a on the the stock A.

The lateral walls of the bit-tang b converge, or incline to each other,both upthe stock is Y lower end of wardly and outwardly, that is to say,the

bit tang is of dovetail cross-section and cessing'of the inner faces ofthe tangs b results in the production of the projections b3 `on theinner faces'of the bits which projections engage the sides of thedistance-block a when the bits are raised into their operative positionby the action of the spring as indicated in Fig. 3 ofthe drawings. The

tangs b of the bits are provided at their upper ends with key slots b4for the reception of a key C which key passes through a transverse slota6 in the stock and su ports the two bits B, It is through this key asanintermediary that the bits' are actuated by the spring. The relativesizeof the key slots b4 and the key C should be such as will notinterfere with the tilting of the bits in their sliding movement to andfrom their operative position on the stock A. The key C has a sllghtnotch or recess c in its under edge for the reception of the disk of aspring cap carried by the upper end of the actuatlng spring.

D indicates the spring for actuating the bits B, B, ythat is to say, forraising the bits from their lower or collapsed positlon (Fig. 4) totheir normal or operative position (Fig. 3) and maintaining them inthedatter position. This spring is located in the bore or axial springchamber a2 of the stock A between the bits and below the key C whichconnects the bits, and is provided at its upper end with a spring cap 0lwhich engages in the notch or recess c in the under edge of the key C.This engagement of the spring cap d in the notch or recess c of the keyprevents the endwise displacement of the key, and the spring cap d ispreferably forked on its upper face so as to straddle the key. The lowerend of the spring D has its bearing on the screw plug P which closes thelower end of the bore or spring chamber a2.

The longitudinal taper of the tang of the bit and the corresponding tangrecess of the stock is preferably, though ,not essentially, a uniformtaper, not only because such a taper is more readily produced butbecause it is more effective in counteracting the effects of wear-andlost motion.

The elemental construction of the stockr A and bits B, B being ofsubstantially the character hereinbefore noted,` the elements are easilyand readily assembled by slidlng the tangs b of the bits into the tangrecesses a of ythe stock froml below, passing essaim.

'is desired to pass the underreamer into 'and through a casing fordrilling purposes, the

bits are drawn down into the collapsed position shown in Fig.'4 of thedrawing. This may be done in any suitable manner, but I prefer to use adevice such as shown applied to an underreamer inFig. 10 of the drawing,in which` L indicates `a lever having a forked end Zadapted'to engagethe wrenchseat fw of the underreamer stock A, and a pivoted brace memberZ provided with a toe l2 adapted to enter a suitable openin in the bitB. When the lever L is applic to the underreamer as shown in Fig. 10 ofthe drawing, the lever L ma be operated to force down the brace mem r land withit the bit B until the spring is compressed and the bits forcedinto the collapsed position.

The bits can then be entered in the casing, or can be confined by aclamp as desired.

For this purpose any suitable means of hold-py sed position may be ingthe bits in the colla employed. In Fig. 8 o the drawing I have shown asemi-circular yoke Y provided at one end with a clamp screw :n and thisis employed y a plying one end of the yoke to one bit a d'tlhe other tothe opposite bit and then tightening up the clamp screw When theunderreamer is in the collapsed condition shown in Fig. 4 of thedrawings the bits are inserted in the end of the casing and the clam Yxremoved. The casing will confine the blts and maintain the under-`reamer in the collapsed position shown in Fig. Iet until the bits passfrom the lower end of the casing, whereupon the expansion of the springD which 'was compressed by the drawing down and forcing inwardly of thebits, will lift the bits into the normal and operative position shown inFig. 3 of the drawing.- As a result of the longitudinal taper of the bittang and tang recessl of the stock, the initial downward movement oftheV bits with relation to the stock produces such a clearance of theparts as will permit of the tilting of the bits required for theirinward or collapsing movement. This also reduces the friction and theconsequent load i on the actuating spring in the reverse movement of thebits. Furthermore, the final uppward movement of the bits on the stockwill eliminate all lost motion from wear or upsetting of the'parts,counteract any tendency of the bits to tilt land thus properly andeffectively support the bits during the cutting operations thereof. Theunderreamer will be drawn into and through the casing in the usual way,that is to say, the upward pull on the underreamer' will bring the outersurfaces of the bits into engagement with the lower end of the casingwhich will hold the bits until the continued upward movement of thestockcompresses the actuating spring' and the recesses b2 of the bit tangsare opposite the distance block ai of thel stock, whereupon the bitswill move inward, or collapse, so that they can pass intoand through thecasing. i

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

v1. In an underreamer, the combination'l bit recesses the lateral.

with a stock havin walls of'wliich are inclined to each other, of

bits longitudinally movable on the stock into and out of operativeposition said bits rovided with tangs having lateral walls w ich areinclined to each other.

2. In an underreamer, the combination with a stock having bitrecesses'the lateral walls of which are inclined to each bther upwardly,of bits longitudinally movable on the stock into and out of operativeposition,

said bits provided with tangs having lateral walls which are inclined toeach other Iupwardl y 3. n an underreamer, the combination with a stockhaving bit recesses the lateral walls of which are inclined to eachother both upwardly andl outwardly, of bits longitudinally movable onthe stockinto and out of operative position, said bits rovided withtangs having lateral walls w ich are inclined to each other "bothupwardly and outwardly.

4. In an underreamer, the combination of a stock havin a distance blockwhich supports the bits 1n operative position and-provided with bitrecesses the latera ywalls ci which are'inclined to'each other, of bitslongitudinally movable on the stock into and out of operative position,said bits provided with tangs having lateral walls which are inclined toeach other.

5. In an underreamer, the combination of a stock having a distance blockwhich supports the bits inoperative position and provided with bitrecesses the lateral walls of which incline to` each other u wardly, of.

bits longitudinally movable on t e stock into and out of operativeposition, said bits pro,-

.vided with tangs having lateral walls which incline to each otherupwardly.

6. In an underreamer, the combination with a stock having a distanceblock whichv supports the bits inoperative position, and

able on the stock into and out of operative position, said bits providedwith tangs havj ative position..

ing lateral walls which incline to eachother both upwardly andoutwardly.

7 Inan underreamer, the combination with a stock having a distance blockat its lower end which supports the bits in operative position, lateralabutmentsforthe bits,

- and bit recesses the lateral walls of which ining bit recesses thelateral Walls of which converge upwardly and outwardly sald recessesadapted to permit the movement of reamer bits longitudinally of thestock.

10. An underreamer bit having shoulders,

and a tang the later-alwalls of which converge in two directions.

l1. An underreamer stock having at the lower end and opposite sideslthereof longitudinally extending bit recesses for the reception ofbit-tangs, said recesses having lat- -eral walls inclined to each otherboth out wardly and upwardly said recesses adapted to permit themovement of reamer bits 1011-.

gitudinally of the stock I,and said recesses communicating at theirupper end.

In testimony whereof I aix my signature,

in presence of two subscribing witnesses.

PATRICK H. MACK. i Witnesses:

G. P. EINER, HUGH M. STERLING.

